cheap flights to miyakojima

hi,
I'm flying from Osaka to Miyakojima and I stay there for 6 nights, then I take a flight from Miyakojima to Naha and I stay there for 7 nights, then I take a flight to Narita airport.
so I check ticket prices at sky scanner and I found ANA and vanilla airlines and the ticket are cheap...very cheap, so I'm concerned that the prices are suspiciously low or the luggage is not included in the prices and when the time to aboard the flight I will have to pay double or something.....
did anyone ever flown with those airlines before? did you pay more then the ticket?
also how early should I book those tickets?
thanks in advance

so I check ticket prices at sky scanner and I found ANA and vanilla airlines and the ticket are cheap...very cheap, so I'm concerned that the prices are suspiciously low or the luggage is not included in the prices

Vanilla does not even fly on these routes! So, I would be very suspicious about that website!

The cheapest airlines from Osaka to Okinawa are probably Peach and Jetstar. Between Naha and Miyako, the prices are silimar between Solaseed, ANA and JAL.

I am not familiar with sky scanner, but rates advertised by ANA typically include all taxes and surcharges; however prices by LCCs like Peach and Vanilla typically require you to add a few hundred yen of hidden fees. In case of luggage on Peach, the surcharge can be over 1000 yen.

I recommend to check the official websites. They usually offer the cheapest rates and full outline of surcharges.

Sorry, Solaseed does not serve Miyakojima.

so which one is the best choice for cheap flights?

The direct flights between Osaka and Miyakojima tend to be very expensive. If you can book them using an air pass, the air pass can be a very good value. About air passes:
http://www.japan-guide.com/e/e2364.html

It is usually much cheaper to fly via Naha. In that case, Peach and Jetstar tend to be cheapest between Osaka and Naha. Between Naha and Miyakojima, I think currently only ANA and JAL are operating, but it is a relatively short and cheap flight if you book in advance (still, it may end up costing about the same or more than the Osaka-Naha leg , though).

Check the airlines' official websites for details.